Although anger is an important emotion underlying overt aggression of great social cost, little is known about the relations between anger and the behaviors with which it is associated. The almost ubiquitous tantrums of toddlers provide a window onto anger which can be so intense as to be otherwise inaccessible to systematic observation. Analyses of 330 previously collected tantrums suggest that the rise and fall of different angry behaviors reflects the momentary level of anger. We propose to construct a quantitative model which relates the observed temporal variation in each of the angry behaviors to the changing intensity of anger which drives them all. The model will be tested against a more detailed tantrum data set now being collected. Because all the easily observed angry behaviors are already incorporated into the model, new measures of tantrum anger are needed for empirical testing. To meet this need while opening up a promising new area of study, we will acoustically analyze the unexplored diversity of tantrum vocalics. Screams, shouts, whines, and cries, recorded by microphones sewn into the child's shirt, will be digitized and spectrally analyzed by DFT. Temporal changes in vocalic probability, duration, F0 characteristics, and dysphonation will be compared to the anger trajectory calculated from the simultaneously videotaped behaviors. We will also test the model with FACS coded facial expressions and global anger ratings by parents and pediatric experts. Among the major benefits of successful modeling would be the ability to scale behaviors by anger intensity, to estimate total or maximum tantrum anger, and to compare anger intensity within and between children (e.g., related to tantrum triggers, parental intervention, and childhood psychopathology). This project will also provide a paradigm for the analysis of such time course data. The innovative nature of this research, and its novel application of acoustic analysis to tantrum vocalics, qualifies this application for the R21 program.